Conveyer system for vehicles



Oct. 28, 1952 B R r AL 2,615,587

CONVEYER SYSTEM FOR VEHICLES Filed June 24, 1949 3 Sheets-Sheet 1 IN V EN TOR.

BY m9 4. mam

p anum/ 1952 F. A. BEYER ETAL 2,61

' CONVEYER SYSTEM FOR VEHICLES Filed June 24, 1949 s Sheets-Sheet 2 Oct. 28, 1952 F. A. BEYER EI'AL 2,615,587

CONVEYER SYSTEM FOR VEHICLES Filed June 24, 1949 3 Sheets-Sheet 3 g VEN TOR. BY W 7 8% A rown Fwd Patented Oct. 28, 195 2 UNI TED S ENT OFFICE -coNvErsasrs'rEMFoRvEHIcLEs Frank -A.'--Beyer-and Ralph A. Bradley, Springfield, Mo., assignors, bylmesne assignments; to ;.Trailmobile lnc a corporation of Delaware implication June 24, 1949, SerialjNo. 101,1 2

This invention relates generally to'vehicles and particularly to a road vehicle for haulingbulk loads of Bortland cement and similar pulverized r .,or granulated. materials .whichshould be protected from contaminationrby moisture and dirt while in transit. ,Thevvehicle I is equipped with an l. there" being installed lengthwise; Within theftank I a .conveyon system for feeding the materialby power from thetank. ;The invention resides particularly in an improved screw conveyor which is 'dividedintoselectively driven sections, combined with improvements in the tank structure to render more eflicient the operation of the conveyor andto provide more uniform distribution =of'the load. a

The improved arrangement was designed primainly for semi-trailers in which the-forward weight load .is supported, by a tractor with the Hrearwardload sustainedby one or more sets of road wheels although it is contemplated also to app th v ame conveyorifsystem to tank trucks ,and'other vehicles as well as to stationary tanks or hoppers. Asapplied to atrailer, it "is desirable to keep trailer weight at a minimum in order ,to carry the greatest payload, consequently it is, important to providefor the screw conveyor a power plantof the least possible weight and bulkoonsistent with efiicient performance. Also, since trailers and trucks which operate over pub .licnroads are subject to regulations limiting the weight load upon the wheels, it-is essential to distribute and maintain the load uniformly inthe tank.

In genera1, the trailer constitutes a chassis .upori, whlchis mounted a full length-tank generallyV -shaped in crossseotion; having a series of gpenings ior loading, and'havin a power drivenscrew or spiral vane conveyor system 10- catedinlthe tank-bottom, arranged to discharge the, material from an end ofthetank. -Resistancetoi the conveyor screw. against rotation increases proportion to'the'length of the tank: in other words, rotation of the screw is resisted for the entire length of the tankif a' one-piece sqrew is used. j} Howeverg'this is unnecessary since the unloadingoperation can be-performed just as; efiiciently if the material is engaged aby the sc rew' near the discharge end'only; in which case 3 the power required to drive the screw' is .de-

creasedproportionately. 1 i I Iheprimary objects of the inventionhave been toreduce the power requirements by splitting the conveyor screw intoindividually driven sections and to provide in conjunction with the conveyor, ;a tank which; is dividedinto compartments to prevent shifting of the -load,- thecompartments -being co-extensive with the respective screwsections to permit-selectiveunloading ofthe com- -partments.

-Furtherobjects have -been toprovide-a:-sectional screw conveyor system having screw sections disposed-one above another withthe sadjoining ends of thesections overlappedandconnecte'd" by a passageway so that the-material: .is

dischargedby positive displacementfromtheend of one screw -section to'the beginning-of the next section and to provide improvements :in the tank "for the screw sections are-established, with" the power unit, transmission system andscrewmearings placedto theexterior of theteink'forcohvenient inspection and service.

In the preferred structure, power f'or-rota'ting the sCreWis reduced to a; minimum by splitting the screwinto two overlapping .sections which are selectively driven, one inadvance of 'another to unload the tank insuccessive sections. v-. A;i.t'er

j one compartment" (if-"the tank --is' unloaded; the

next screw section is coupled: forunitary rotation with the-first section tounload thet-next compartment by combined operation .of .aboth' screwsections. {Thisarrangementsresults .in a

substantial reduction in power-requirements with the result that a smaller powerplant-vmayhbe utilized, andif' desired, permits th e compartments to be unloaded separately.

Because of the character of the mater-i'aL, itv tends to shift While the vehicle is intrans'itwith the-result that the original weight distribution is disturbed. By' providing compartments-gimme .dividual loading; hatch which includesa c over or trap door 1 to seal off the compartment a fter loading. a

In thepreferred disclosure, the tank is ,divrided into a forwardandrearward compartment-by a central partition, the material being-discharged zThe ;.b.0tt0m .Of v-the ufol ward gcompantment is higher. than. that of-the rearward; compartment so that the respectivetscrew sectionsi liezz'inv parallel planes one directly above the 1other,t. wi-th their adjoining ends overlapped atr theijuncture of-the two compartments and with several turns of-each screw effective to. feed positively the-material from the upper screw -section to. thelower. Since the loottom'ofthe two tank compartments lies atdiiferent-levels, there is providedianaofiset enclosing the overlapping screw "sections and edon thewend -walllof the offsettandtheaend of the other section extends through a bearing mounted on the central partition, passing into a tunnel extending crosswise of the shell. The overlapping ends of the screws are connected to the driving apparatus by respective sprocket and chain drives placed side by side, providing a direct, close coupled connection to the driving apparatus.

The driving mechanism includes a clutch and motor, the motor being permanently in driving connection with the rearward screw section and being selectively coupled to the forward screw section by the clutch. In unloading a full tank, the clutch is uncoupled from the forward screw section so that only the rearward screw section is driven to unload the rearward compartment, the

forward screw section remaining stationary. After the rearward compartment is emptied, the

;' clutch is shifted to couple the forward screw section, whereupon both sections rotate in unison,

the material being conveyed from the forward compartment, fed to and conveyed by the rear screw section through the now empty rear compartment to the discharge chute. Due to the selective driving of the screw sections, the power requirements are materially decreased while at a the same time, by reason of the overlapping screw sections and tank structure, the operation is positive and efiicient. & The screw arrangement is of particular ad- -vantage as applied to a semi-trailer since the forward end of the trailer necessarilyis higher than the rearward and to accommodate the fifth wheels The two level screw system complements this design by permitting the bottom of the forward compartment to be made higher than the I rearward one.

Further details and advantages will be apparent from the following description in conjunction with the accompanying drawings so that those skilled in the art will comprehend fully the various modifications of which the invention is capable.

' In the drawings:

Figure 1 is a general side elevation of a trailer having a tank body provided with the improved sectional screw conveyor system.

i Figure 2 is a longitudinal section taken through thetank, illustrating the general arrangement of the tank bottom and the driving connections between the screws and drive shaft.

Figure 6 is a sectional view taken on line il't, Figure 2, further illustrating the tank, particularly the overlapping relationship of the screws at the center whereby the material is fed from the upper to the lower screw section.

Figure '7 is a sectional view taken on line B -l, Figure 2,,illustrating one of the intermediate partitions of the tank together with the structure for supporting an intermediate bearing for the conveyor screw.

Figure 8 isa longitudinal sectional view similar to Figure 3, illustrating a modified arrangement by which the forward screw is driven at its for- 4 ward end, as distinguished from the arrangement shown in Figure 3.

Figure 9 is a longitudinal section similar to Figure 2, illustrating a modified arrangement, one of the screw sections having a reversed pitch, and both sections being connected to a discharge chute for direct discharge into the chute by either section.

Figure 10 illustrates a further modification in which the screw sections are placed end to end in axial alignment, there being provided a separate discharge chute for each screw section.

Figure 11 is a longitudinal sectional View taken on line H! 1, Figure 10, illustrating the driving apparatus for selectively driving the screw sections of Figure 10.

In the drawings, the conveyor structure is disclosed as part of a semi-trailer designed especially for hauling bulk loads of Portland cement and similar pulverized, granulated or crushed materials which can be handled by screw conveyors. However, it will be evident that the improved system is not restricted to vehicles but can be utilized for any other service which involves the conveying of materials by spiral vanesor screws, particularly those installations which, by reason of length, can be made more efficient by breaking the screw into independently driven sections.

Referring to Figure 1, which discloses a preferred form of the invention, the tractor is indicated generally at Iii, having a fifth wheel H for supporting the forward end of the semi-trailer l2, the rearward end of the trailer being supported by sets of wheels l3i3. A landing gear or prop I4 is mounted toward the forward end of the trailer to support it when it is uncoupled from the tractor. The structural details of the semitrailer are well known in the art and are not relevant to the present disclosure and for this reason are not disclosed in greater detail. It is to be noted however that the two level conveyor and tank is particularly adapted to semi-trailers since the bottom of the tank is higher at the forward end to accommodate the fifth wheel, following the general practice in trailer construction.

As shown in Figure 5, the trailer chassis constitutes longitudinal channels i5-IE joined by transverse members l6 arranged to form a foundation for the tank ll. The tank is stabilized upon the chassis by means of bracing members I8 (Figures 1 and 5) which rise from the chassis along opposite sides, the upper ends of the members being joined to the sides of the tank. The tank shell is constructed of sheet metal sections which may be joined together by riveting or welding following conventional construction practice.

The tank I1 is generally V-shaped in cross section and contitutes a top member 19 joined by side walls 20-28 which converge downwardly toward each other, terminating on opposite sides of the screw conveyor indicated generally at 2|. As shown in Figure 2, the tank is divided longitudinally into a forward compartment 22 and a rearward compartment 23 by an intermediate partition 24. In the forward compartment 22, the converging side walls are joined by a radial trough section '25 (Figure '7) developed from the center of the screw section so that the arcuate trough closely embraces the lower portion of the screw. In order to accommodate the screw section for the rearward compartment, the side walls converge toward a trough 29, preferably forming a continuous part of the side-' wallsand having a radialibottomigl, following the-radius of the rearward screw section (Figure 6). The top and side walls of the tank shell therefore are con- .tinuo'usfor the fulllength of the trailer, the rearward compartment however being provided with -the-oifsetscrew trough-26 so that the two screw sections may be placed in horizontal planes one above the other with their intermediate adjoining ends in overlapped relationship. Thus, the upper screw section and'its trough'25 form a step at the forward end of the tank which overhangs the tractor and'provides clearance for the fifth wheel. v'iAs'showninfiigures 2 and 6, the forward sec-- "tion is indicated at 28 and the rearward section at 38, with the spiral vanes of the screws extending into thepassageway' 32 formed at the juncture of the forward and rearward tank compartments so that the material is fed by positive displacement'frorn the end'of one screw vane to the beginning of the next, since both rotate in the same direction. The driving arrangement for the-"screw sections is such that the rear section is in constant driving connection with the power source while the forward section can be connectedf or disconnected as required. In unloading the 'vehicle, the rear screw section'preferably is operated until the rear compartment is emptied then the forward section is engaged by operating a clutch so that both sections are driven. In this manner the material discharged by the forward screw is fed to the rearward one and finally discharged through the rear outlet 3 l.

By reason of the tendency of cement or other pulverized material to shift while the vehicle is in transit, there is preferably provided, in addition to the intermediate partition 26, one or more supplemental partitions 33 in the forward and rearward compartments 22 and 23. The purpose of this arrangement is to prevent the material from flowing due to acceleration and deceleration "or'other factors tending to disturb the original weight distribution.

The material is loaded into the tank through openings 34 formed in the top of the tank, there being provided preferably one opening for each sub-division of the tank. These openings are provided with trap doors 35 hinged as at 36, preferably including gaskets to prevent water from entering the tank'and possibly ruining the contents. The top of the tank between the openings includes a longitudinal flat section 31 for the safety of the operator when it is necessary to open and close the trap doors. The trailer is loaded by successively filling the several sub-divisions in any well known manner, for example, by a chute leading from an elevated hopper so that the material flows by gravity into the tank. If the tank is tobe filled partially, an equal quantity of material is discharged into each sub-section so that the load is evenly distributed throughout its length. v

As shown in Figures 2 and 3, the forward screw section is journalled in bearings 38 and 39, the

bearing 38 being secured to the forward wall 40 and the bearing 39 being secured to the intermediate partition 2d. In order to permit installation of the screw, the wall 40 includes an opening of sufiicient size to permit entry of the screw, the bearing 38 including a cover plate 4| sufficiently large'to close the opening. The bearings '38 and 39 are not detailed since they may follow any conventional design. By reason of the extended length of the screws, there is provided also -an intermediate support bearing 42 which depends downwardly from an angle iron 53 secured GB journ'alled in bea'ringsGI-Bl mounted upon the platform 62, the counter shaft being driven to the supplementalpartition as; Thebearing M includes a vertical bracket fi l-secured by screws to theang-le iron, the bearing-being of the-split type to permit it to be placedon opposite "sides of the screw'sec'tion, 'fthen assembled in position. In order to accommodate-the bearing,- the vane of the screw is 'interruptedas at' l5, leaving-a slight clearance on opposite sides of the bearing as shown. This interruption is relatively-short and has little effect onthe efficiency of the screw.

The screw maybe of any" desired construction? for example, it may constitute-ashaft' 46 and a -va'ne 41 formed of sheet metal-sections welded tothe shaft.

Therearward screw section" 38' is journalled in bearings 48 and 50, the bearing 48 being mounted upon the vertical wall section-5| of the offset which delineates the passageway between-the front-and rear tank compartments. The rearward bearing 58 is mounted upon the rearwall 5'2 of discharge casing-53, communicating-with the rear-wall 54-of the tank. Discharge casing -53 includes a removable cover 55- and the casing is detachably mounted upon the tank wall: 54 to permit :removalor assembly of screw 'til from the rear-end'of the tank. The screw" 30 is provided with an intermediatebearing 42 similar to the intermediate bearing-for screw section 28.

The respective screws 28 and '30 are s'electively driven by means of-a motor 5t and a transmission system which is mounted along oneside of the trailer as shown in Figures 3,-4'and 5.

' The'motormay be'ofany type, preferably alight weight gasoline motor equipped with agear reduction unit Til and having a control clutch which may beregulated by the lever" 58. The

motor ismounted upon a lateral base supported "by the I-beams 59 (Figure 5) extending laterally from the" chassis. The respective screw sections 28- and 30- are driven by means ofa-counter shaft from motor 55 by means of the-motor sprocket 63, sprocket chain 64, and sprocket '65 whichis keyed to the countershaft 60.

The rearward screw section 30 is-driven by sprocket- B6 keyed to counter shaft '60, the screw having a 1 driven sprocket 61 --connected to sprocket 66 by chain- 68. By this arrangement the rearward screw 30 is in constant driving connection with the motor so thatwhenever the clutch lever 58 is in'its driving positiornthe rear screw is rotated. I

' The forward screw section 28, is driven independently of the rearward section and for this purpose is coupled to the counter shafttil by means of a clutch. The drive "is transmitted from counter shaft- 60 through a counter shaft sprocket- 69, connected to the screw sprocket '19 by meansof a chain H. Sprocketi69is loosely journalledupon the counter shaft and a driving counter shaft 60, sprocket chain 68 to the rearward-screw section Stand if the screw clutch lever Hisin disengaged-position as shown, the forward screw will "remain stationary but if' lever 74 is moved to clutch engaging position, both screw sections will be driven in unison.

' The screw sections are rotated at a relatively slow speed and the chain and sprocket drive between the moto and screws is arranged to provide an appropriate speed reduction. For this purpose motor sprocket 63 is proportionately smaller than counter shaft sprocket 65 and also the counter shaft sprockets 66 and 69 for the screw sections are proportionately smaller than the screw sprockets 61 and it. It has been found that a screw speed of 75 R. P. M. provides a desirable rate of discharge but the speed necessarily depends upon the pitch of the screws and may be varied to suit the type of material and other factors.

As shown in Figures 2 and 5, the tank is provided with a transverse tunnel '18 to accommodate sprocket chain ll while the chain 68 passes beneath the forward compartment of the tank H so that both chains are isolated from the material in the tank. The tunnel is is formed by a sheet metal panel 80 having its upper edge secured to the intermediate partition 24 and extending downwardly at an angle to the partition with a bottom plate 8! joining the lower edge of panel 88 to the lower edge of the partition 24. An intermediate horizontal plate 82, secured between the partition and panel 80, forms the top wall of the tunnel. The chain l! enters the tunnel through a slot 83 formed in the tank wall 20 (Figure In unloading the trailer, the motor 58 is started, then the motor clutch lever 58 is actuated to drive counter shaft 60, causing the rear 'the same time. By virtue of the inclined walls 29 of the tank shell, the material flows by gravity to the screw so that all the material is discharged. When the selector clutch lever 14 is shifted to the right as viewed in Figure 3, the

clutch sleeve 72 is engaged with the mating toothed hub 72a. of sprocket 69 (Figure 4) thereby transmitting the drive from counter shaft 60 to sprocket of the forward screw section 28. In this position both screw sections are driven unitarily and in the same direction so that the material is conveyed from forward tank compartment 22 through passageway 32 to screw section 36 the material passing longitudinally through trough 26 of screw 30 to the discharge chute 3!. In order to prevent sifting of the material through the chute, there may be provided a cover plate (not shown) to close ofi the chute except during the unloading operation.

By the provision of a divided conveyor screw, a great deal less power is required and consequently a smaller driving motor may be utilized. When the operation of unloading a fully loaded tank is commenced, it is unnecessary to drive the forward conveyor screw section since the material necessarily must first be discharged from the rear compartment before commencing the discharge from the forward compartment. This of course eliminates the friction involved in the useless operation of the forward screw section while the rearward compartment is being unloaded.

It will be apparent that more than two screw sections can be utilized depending entirely upon the length of the tank and other determining factors. A somewhat modified arrangement is disclcsedin Figure 8 whereby the screw sections are driven at their forward ends instead of at overlapping ends as in Figure 2. For this purpose there is provided a counter shaft 60a which is connected to the motor 56 by chains and sprockets in the manner above described. In this arrangement the counter shaft sprocket Sea and forward screw sprocket 10a are disposed at the forward end of the screw by virtue of the extension shaft 35. A clutch sleeve 12a. is slidably keyed to extension shaft 85, engageable with a cooperating clutch collar 86 keyed to the counter shaft. The rearward screw section is in constant driving connection with the counter shaft 6M by means of the sprocket 66a and chain 68a which passes over a sprocket (not shown), mounted upon the forward end of the rearward screw in the same manner as shown in Figure 2. Thus, the'rearward screw section is driven when the motor clutch is thrown into engagement so that the rearward tank compartment first is emptied after which the clutch lever Ma is shifted to the right to couple extension shaft to counter shaft 69a to drive the forward screw section.

The modified structure illustrated in Figure 9 is substantially thesame as disclosed in Figure 2 except that the rearward discharge chute 3! is omitted and there is provided instead an intermediate chute 86 communicating with the passageway 32 at the juncture of the overlapping screws- In this disclosure, the lead of the rearward screw section 38 is reversed so that both sections can be rotated in the same direction by a transmission system similar to that disclosed in Figure 3 to convey the material from opposite ends of the tank towards the center for discharge. Thus, both screw sections discharge directly into chute 85 instead of transferring the material from the forward to the rearward screw section as practiced in the previously disclosed arrangement.

One virtue of this arrangement is that the material in the compartments is more complete- 1y segregated, making it more practical to discharge the contents of the respective compartments to different receiving points. Also, both compartments can be unloaded at the same time for greater speed by driving both screw sections but in this instance, greater power is required.

In the preferred mode of operation, the clutch lever 53 of motor 56 is shifted to drive the rear screw section 36 while the forward section 28 remains stationary. After the rear compartment is unloaded, the screw section for the forward compartment is driven by shifting the selector clutch lever "it, as previously described. It will be noted that when the screw section 28 is coupled to the transmission, the rear section 36 also is in rotation since it is coupled permanently to the counter shaft Ell. However, if desired, the transmission system can be altered readily to provide selective coupling for both screw sections in which case either the forward or rearward screw section can be coupled so as to unload the compartments selectively.

The chute 86 includes a closure, indicated at 87, to prevent materia1 from spilling by gravity from the tank. The closure in the present instance is in the form of a door hinged as at 88 to the bottom of the chute, with a wing nut 90 97 keyedto a respective extension shaft.

9 arranged to clamp thedoor in closed position. It will beapparent thatthe'closure maybe of any conventional construction .arrangedto. be conveniently opened and closed for loading and unloading the tank.

In the modified arrangement. disclosed in Figure 10, the screw seotionsarelocated axially in-alignment with each other instead of offset and the tank. is provided with two discharge chutes :SI and 92, one for each compartment. The screw sections. Hand 30 are driven selectively in thesame manner. as above outlined and since the. sections are placed endto .end, the bottom of the tank is not offset as in theprevious structures.

It will be noted in Figure 11 thatthe screw sections are driven at their opposite ends-instead .of centrally, for which purpose the transmission system includesv a forward extension shaft 93 and a rearward shaft 9d. The outer ends of. the respective screw. sections extend through the opposite end walls of the tank and each screw section is provided with a sprocket 95 connected by a sprocket chain. 96 to a sprocket The rearward extension shaft 94 is permanently coupled to the transmission while the forward extension shaft 93 is selectively coupled by the of the forward compartment constituting a'conveyor trough and. the rearward compartment havinga conveyor trough disposedbelow the planeof the conveyor trough of the forward compartment, the conveyor trough of the forward compartment including a substantially vertical passageway open to. the trough of the rearward compartment, a respective forward and rearward conveyorscrew section extending through said re-, spective troughswith the inner adjoining end portions of the sections being disposed one above the. other in overlapping relationship in the.ver-' tical passageway between the forwardand rearward troughs, the forward screw section having a shaft extended rearwardly through said intermediate partition and the rearward screw section having a shaft extended forwardly through the end of the rearward trough, respective driving means connected .to theextended shafts, said respective driving means being disposed laterally of the. screw sections and adapted to rotate said forward and rearward conveyor screw section selectively to provide selective unloading of the forward and rearward compartments, and a laterally extended housing mounted upon the intermediate partition within the tank to enclose the driving means for the forward'screw section the said housinghaving an opening to the exterior of the tank with the said driving means extending into the housing through said opening.

As shown, the chutesare modate the fifth wheel, anintermediatecom necting wall joiningv the. forward 7 and. rearward compartment bottoms, the said wall being. spaced longitudinally from-the partition to provide'ja substantiallyvertical passageway extending from the forward to the rearwardcompartment, a sectional conveyor system constituting. respective screwconveyor sections disposedv substantially in horizontalplanes oneabove theotherwithin the bottom of the said forward and rearward .compartmentswiththe. intermediate ends of the screw sectionsoverlappingone. another in said vertical passageways, the elongated .tankhaving a-discharge-opening in. its rearward compartment communicating with the rearward end .of said conveyorscrew-section, the screw conveyor section in the rearward compartment having a shaft at its forward end extending outwardly of-thetank through said intermediate connectingvwalL- the screw conveyor section in the forward compartment having a shaft extending rearwardly-through the said partition, bearings forsaidshafts; oneof said bearings being mountedupon' the forward side of "said-intermediate well at the exterior of the tank, the other of said bearings being mounted" upon-the rearward side of said'partition; andahousing extending transversely-within said tank mounted upon the rearward side'of the-partition to enclose'and protect the bearing mounted thereon from the contents ofthe tank.

3. In a semi-trailer fortransporting pulverized materials, an elongated tank havinga fifth wheel at its forward end-and road wheelsat its rearward end-,said tankhaving a partition at a point intermediate itslength providing a. forward and rearward compartment, the forwardcompartment having its bottom disposed at an elevation above -therearward compartment to accommodate the fifth wheel; an intermediate connecting wall joining-the forwardandrearward compartment bottoms, thesaid wall being-spaced longitudinally from the vertical partitiorrto provide a: substantially vertical passageway, extending from the forward-to the rearward compartment, asectional conveyor system constituting-respective screw conveyor sections disposed substantially in horizontal planes one-above the other within the bottom of the said forward and rearward compartments, the intermediate endsof the screw sections being overlapped withrespectto one another in said vertical passageway, the elongatedtank having a discharge opening. invits rearward compartment communicating with- .the rearward end of said conveyorv screwsectiomthe screw conveyor section in the rearward compartment having a shaft at its forward end sextending outwardly of the-tank through the-said intermediate connecting wall,-the-screw conveyor section in the forward compartment-havinga shaft extending rearwardly through the saidpartition, bearings for said shafts, one'of said-bearings being mounted upon the forwardside-of'said intermediate wall to the exterior of thetank; the other of said bearings, beingcmountedrupon the rearward side of the partition, a housing extending transversely within said tank mounted upon 11 the rearward side of the partition to enclose and protect the bearing mounted thereon from the pulverized material contained in the tank, the said housing having an opening communicating with the exterior of the tank, and driving means connected respectively to the said shafts to rotate one or both of the said screw conveyor sections to discharge selectively the contents of one-or both of said compartments.

4. In a semi-trailer for transporting pulverized materials, an elongated tank having a fifth wheel at its forward end and road wheels at its rearward end, said tank having forward and rearward end walls and a vertical partition at a point intermediate its length providing a forward and rearward compartment, the forward compartment having its bottom disposed in a plane above the rearward compartment to accommodate the fifth wheel, a vertical connecting wall joining the forward and rearward compartment bottoms, the

said vertical wall being spaced longitudinally from the vertical partition to provide a vertical passageway extending from the forward to the rearward compartment, a sectional conveyor system constituting a pair of screw sections disposed substantially in horizontal planes one above the other within the bottom of the said forward and rearward compartments with, the inner ends of the sections overlapping one another in said vertical passageway, the elongated tank having a discharge opening in its rearward compartment communicating with the rearward end of the conveyo screw section, the screw conveyor section in the rearward compartment having a shaft at its forward end extending outwardly of the tank through said vertical connecting wall, the other of said conveyor sections having a shaft extending rearwardly through the said vertical partition, bearings for said shafts, one of said bearings mounted upon the forward side of the vertical connecting wall to the exterior of the tank, the other of said bearings mounted upon the rearward side of the vertical partition, a housing mounted upon the rearward side of the vertical partition enclosing the said bearing and having an opening leading to the exterior of the tank, the opposite ends of said screw conveyor sections each including a shaft extending outwardly through the forward and rearward end Walls of the tank, and respective bearings mounted externally upon said forward and rearward walls for supporting said shafts, whereby the bearings at both ends of the conveyor screw sections are isolated from the contents of the tank and accessible from the exterior thereof.

5. In a semi-trailer for transporting pulverized materials, an elongated tank having a partition at a point intermediate its length providin a forward and rearward compartment, the forward compartment having its bottom disposed in a plane above the rearward compartment, a connecting wall joining the forward and rearward compartment bottoms, the said wall spaced longitudinally from the partition to provide a substantially vertical passageway extending from the forward to the rearward compartment, respective screw conveyor sections disposed substantially in horizontal planes one above the other with the intermediate ends of the screw sections overlapping one another in said vertical passageway, the screw conveyor section in the rearward compartment having a shaft at its forward end extending outwardly of the tank through said intermediate connecting wall, the screw conveyor section in the forward compartment having a shaft extending rearwardly through the said partition, respective sprockets mounted on said shafts, one of said sprockets being disposed at the forward side of said intermediate wall at the exterior of the tank, the other of said sprockets being disposed at rearward side of said partition, a housing extendin transversely within said tank at the rearward side of the artition to enclose the sprocket therein, and having an opening to the exterior of the tank, a power unit mounted alongside the tank, the power unit including a pair of driving sprockets aligned with the sprockets of the conveyor screw sections, and respective chains connecting the aligned sprockets, one of said chains extending transversely through the opening in said housing and the other of said chains extendin transversely beneath the tank.

6. In a vehicle for transporting pulverized materials, an elongated tank having an intermediate partition providing a forward and rearward compartment joined by an intermediate offset in the tank bottom, the rearward compartment including a discharge opening, a rotatable conveyor screw section in each of the compartments disposed substantially in horizontal planes one above the other with the intermediate ends of the sec tions overlapped, the forward screw section having a shaft extending rearwardly through the intermediate partition and the rearward screw section having a shaft extending forwardly through said intermediate offset to the exterior of the tank, a respective driving sprocket mounted upon the extended shafts of the screw sections, a housing within the tank enclosing the driving sprocket of the forward screw section, and open to the exterior of the tank, a power unit including a counter shaft externally of the tank parallel with and laterally adjacent the overlapped screw sections, a sprocket loosely mounted upon the counter shaft having a chain extending into said housing and passing over the sprocket therein for selectively driving the forward screw section, a second sprocket fixed upon said counter shaft having a chain extending beneath the tank bottom and passing over the sprocket at the said intermediate offset providing a fixed drive for the rearward screw section,

' and a shiftable clutch element on said counter shaft arranged selectively to uncouple the loose sprocket from the counter shaft, whereby the rearward compartment may be unloaded in advance of the forward compartment by uncoupling said clutch to cause the forward screw section to remain stationary while the rearward screw section is driven.

FRANK A. BEYER.

RALPH A. BRADLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 726,711 Lewis Apr. 28, 1903 1,059,889 White Jan. 21, 1913 2,029,297 Peyton Feb, 4, 1936 2,110,262 Curtis Mar. 8, 1938 2,131,907 Surdy Oct. 4, 1938 2,290,460 Winsor July 21, 1942 2,495,907 Reinking Jan. 31, 1950 

